It is well known in the pharmaceutical industry to count a desired number of pills or capsules or the like for dispensing to patients in hospitals or pharmacies. Typically, large institutions utilize large and expensive robotic dispensers which store a number of different pharmaceuticals on board and utilize computerized methods of determining the number of units dispensed. One such method is to store a size and weight for each pharmaceutical in the onboard computer so that a desired number of units can be dispensed based on a differential weight determination.
Small pharmacies do not typically have access to large robotic units and very often, pharmacists must count pills manually using a tray, which is very time consuming and prone to error. Repeat counting may be instituted to ensure accuracy, however, this adds to the dispensing costs.
Some attempts have been made to provide small portable dispensing units suitable for smaller pharmacies and the like, where a vast number of different types of pharmaceuticals may be dispensed, having unique sizes, weights, shapes and coatings.
U.S. Pat. No. 3,386,618 to Gilbert teaches a rotating bowl having an intermediate, annular, flat and horizontal surface located between the top and bottom of the bowl. A stationary spiral guide ramp comprising an inner spiral and an outer spiral is positioned inside the bowl such that which when the bowl is made to rotate below the stationary ramp, small objects, such as pills, placed in the bowl are caused to move upward inside the bowl and separate into single file. A series of ribs on the inner surface of the bowl aids in causing the pills to move upwards along the wall of the bowl and along the spiral ramps. An annular element is positioned about the top edge of the bowl and is rotated at a speed faster than that of the bowl, acting as a centrifuge to position the pills at an outer and slightly lower edge of the annular element, where they fall through an outlet and are counted by some counting means.
The unit of Gilbert relies on the weight of the pills to avoid stacked pills being carried up the second inclined surface to the top of bowl and ultimately counted as a single pill. Applicant has found that given the diversity of pill shapes and sizes, as well as the types of coatings used in some pills, that one cannot rely on weight alone to separate stacked pills. Although many types of pills naturally line up in single file on the ledge, flat pills pile on top of one another and small pills sit side by side. Thus, two pills appear as one to the optical sensor.
It is further taught by Pillon in U.S. Pat. No. 4,013,192, that the counting aspect of the apparatus of Gilbert can be improved by the inclusion of an exposed slide ramp leading to an optical-based counter employing a photoelectric sensor. A gate located at the bottom of the slide acts to direct the counted pills into a prescription bottle. After the pre-programmed number of pills is dispensed, the gate is pivoted and the remainder of the pills is directed to a stock pill bottle. The apparatus of Pillon is capable of dispensing and counting only a small number of pill types and is not adaptable to handle the enormous variety of shapes and sizes found within pharmaceuticals today.
It is clear that there is a need for a reliable, accurate device for counting a wide variety of pharmaceuticals regardless of size, shape, weight or surface coating and particularly that is suitable for small pharmacies to reduce the cost of prescription dispensing.